In a suspended ceiling system having main runner members and cross members arranged in a grid pattern to support ceiling panels, the present invention is directed to the structure of the members and to the connection used between cross members and the main runner.
Suspended ceiling systems utilizing inverted T-shaped members for both the main runners and the cross members are known. An example is disclosed in U.S. Pat. No. 4,601,153, whose disclosure is incorporated by reference. The runners, as disclosed in this patent, have an inverted T configuration with a central web connecting a bead portion to two outwardly extending flanges, which flanges extend substantially in a single plane, which is substantially the plane of the panels being supported on these flanges.
To interconnect the cross members into the main members, the members may be provided with a tongue-like connecting element, which may be integral as disclosed in the above-mentioned patent or may be a separate element, which is secured on the cross member such as disclosed by U.S. Pat. No. 4,108,563.
In the U.S. Pat. No. 4,601,153, the connecting tongue has a portion cut out and bent out of the plane to form a first abutment surface, another portion pushed out of the plane of the tongue to form a second abutment surface, and is provided with a step to form a third abutment surface. When the tongue is inserted through a slot in the main runner from one direction and a second tongue of a second cross member is inserted in the opposite direction, the first abutment of the first tongue engages the second abutment of the second tongue on one side of the web of the main runner, while the second abutment of the first tongue is engaged by the first abutment of the second tongue, and the third abutments engage each side of the web to lock the cross members in the assembled position.
An advantage of having the connecting element as a separate element that is secured to the web of the flange is that the connecting elements can be made separately and used with different style cross members. This provides a greater flexibility in the manufacture of runners for a suspended ceiling grid to provide different shapes and structures. It is also desirable to construct the various flanges and abutment surfaces so that they may be passed through the slot in the web of the main runner without becoming hung-up or catching on portions of the runner.